This proposal outlines the plans and procedures for evaluation of presently available monoclonal antibodies prepared against a cysteine proteinase (UCP) purified from the urine of gynecologic cancer patients in order to explore the potential usefulness of UCP as a clinical tumor marker in the context of gynecologic oncology. Cathepsin B, a cysteine proteinase, has been frequently reported to be found in the extracellular environment in association with metastatic tumor and has been linked to tumor invasion and metastasis formation in human and animal malignancies. Recent evidence reported in the literature and also presented in the Preliminary Studies strongly indicates that the cysteine proteinase activity associated with malignant tumor represents an enzyme significantly different from normal tissue cathepsin B. It is not, presently, know what portion of the tumor associated cysteine proteinase activity can be attributed to this so-called "cathepsin B-like enzyme" or whether all malignant tumors secrete the same form of cysteine proteinase. Our approach is to use monoclonal antibodies with their inherent specificity to provide the means to address these questions. We have 64 hybridomas presently frozen in liquid nitrogen which have tested positive for UCP. in an evaluation of a limited number of this hybridoma pool, three have been found which produce an IgM antibody which can differentiate between human liver cathepsin B and UCP. To our knowledge, successful production of monoclonal antibodies against any of the cysteine proteinases has not been previously reported. We propose to use this pool of hybridomas to define the specificity, cross-reactivity and avidity of the monoclonal antibodies and to develop an enzyme-linked immunosorbant assay (ELISA) for quantitation of UCP. The long range goals are to use the developed ELISA in a preclinical trial to evaluate the usefulness of UCP as a tumor marker and to use selected monoclonal antibodies against UCP for development of immunohistological procedures for evaluating UCP antigen distribution in normal and tumor tissue.